extreme fast charge and battery cost implicationsbattery cost analysis – the spreadsheet model...
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EXTREME FAST CHARGE AND BATTERY COST IMPLICATIONS
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2017 DOE Vehicle Technologies Office Annual Merit Review and Peer Evaluation MeetingWashington DC, June 5-9, 2017
HTTP://WWW.CSE.ANL.GOV/BATPAC/HTTP://AT.INL.GOV/HTTP://NREL.GOV/TRANSPORTATION/
This presentation does not contain any proprietary, confidential, or otherwise restricted information
CHRISTOPHER MICHELBACHERIdaho National Laboratory
Project Title: Extreme Fast Charging, Project ID: ES304
SHABBIR AHMED, PAUL A. NELSONArgonne National Laboratory
Budget Total FY16 project funding: $775k Funding by Lab: $300k (ANL), $250k
(INL), $225k (NREL) Funding for Battery Cost task: $75k Total FY17 funding: $0
Collaborations / Interactions Argonne National Laboratory, Idaho
National Laboratory, National Renewable National Laboratory Automotive OEMs, Utilities, EVSE
manufacturers & network operators, Battery developers
OVERVIEW
Timeline Project start date: July 2016 Project end date: January 2017
BarriersDevelopment of BEV batteries that meet or exceed DOE/USABC goals Cost Performance
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www.anl.gov
RELEVANCE, OBJECTIVES
RELEVANCE BEV owners would prefer recharging times to be similar to that of gasoline
refueling in ICEVs
Combination of fast charge and a network of high capacity chargers canminimize range anxiety
Fast charge capability can promote the market penetration of BEVs andsignificantly improve the utility (or eVMT) of a BEV
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OBJECTIVESObjectives Identify technical gaps in fast charging technologyAssess the knowledge base of the fast charging capability of
automotive batteries Identify R&D opportunities to improve fast charging ability
Benefit to DOEAid in development of strategic program plan for fast charge applications
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APPROACH
APPROACH Convened an industry stakeholder meeting
to capture direction of fast charge technology and product readiness Extensive review of the literature
Battery Cost Analysis
– The spreadsheet model BatPaC has been used to design the battery pack and to estimate its cost in large volume manufacturing
– Explore the effect of design and properties
– Identify opportunities for improvement and R&D needs
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TECHNICAL ACCOMPLISHMENTS AND PROGRESS
ISSUES AND CHALLENGES WITH FAST CHARGING
Lithium plating / deposition occurs on the anode above a threshold current density
Cell temperature rise during charge can be an issue
Durability of cells are likely to be affectedPlated Lithium
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Defining a baseline battery pack and performance
Pack Requirements / Design Specification
Cathode – Anode Chemistry NMC622-Graphite
Pack Energy, kWh 85
Pack Rated Power (10-s burst), kW 300
Pack Voltage, V 900
No. of cells in battery pack 240
Maximum Allowable Current Density (MACD)*, mA/cm2 4
Charging Time, ∆SOC=80%, min 60
Cell Temperature before Charging, °C 10
Charging Time, ∆SOC=80%, min 60
Non Fast-Charging Battery:Increasing the State of Charge (SOC) by 80% in 60 minutes
Calculated ResultsMinimum Charger Power Needed, kW 77Anode Thickness**, µm 103Heat Generated during Charging (battery pack), kWh 1.45Post-Charge Cell Temperature, ∆80% SOC (no cooling) °C 25Cell Cost to OEM, $ / kWh $103* To avoid lithium deposition, Gallagher et al, J. Electrochem. Soc. 163(2) A138 (2016)** Anode/Cathode thickness ratio = 1.12 10
Fast charge limits anode thickness, increases costCost increases sharply for charge times faster than 15 min
The maximum anode thickness of 103 µmis limited by sustained power requirement
Charging faster than 55 min is limited byMACD=4, requiring thinner anodes
A 460 kW charger is needed for theselected battery to be charged∆SOC=80% in 10 min
MACD = Maximum allowable current density to avoid lithium deposition
NMC622-Graphite85 kWh, 300 kW
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Heat generated during charge raises the cell temperatures
Cooling is not needed for the designed cells
With faster charging, current through the cell increases
– More heat is generated– Cell temperature increases
At charging times less than 55 minutes– Current density capped at 4 mA/cm2
– Thinner electrodes needed– Cell area increases– Cell mass (inactive materials) increases
more than increase in heat generation– Post-charge cell temperatures are lower
No cooling is needed if 40°C is tolerable (initial cell temperature at 10°C)
NMC622-Graphite85 kWh, 300 kW
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Anodes with higher allowable current densities will lower the cost of fast charge batteries
For a 10-min charging battery, $37/kWh cell cost savings is possible, if the MACD can be increased from 4 to 6 mA/cm2
For a 20 min charge– At < 11 mA/cm2 , thinner electrodes needed, cost increases– At > 7 mA/cm2, cooling is required
A 15 min charge raises the threshold to 14.8 mA/cm2
– At < 15 mA/cm2 , thinner electrodes needed, cost increases– At > 7 mA/cm2, cooling is required
A 10 min charge requires thinner electrodes, costs more, cooling above 7 mA/cm2
NMC622-Graphite85 kWh, 300 kW
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Lower area specific impedance (ASI) will reduce heat generation and cell temperature rise
At MACD = 4 mA/cm2
– No cooling is needed• Current is low, heat generated can be
absorbed by cell thermal mass• Thin electrodes, high cost
At MACD = 8 mA/cm2
– Cooling is needed if ASI > 14 Ω-cm2
• More current, more heat generated• Thicker electrodes, lower cost
Effect of ASI on cell cost is very small– May add cost to meet cooling needs
35 Ω-cm2 10 Ω-cm2 ∆
4 mA/cm2 $196.1 / kWh $195.8 / kWh 0.2%
8 mA/cm2 $140.4 / kWh $140.0 / kWh 0.3%
NMC622-Graphite85 kWh, 300 kW10 minute charge
NMC622-Graphite, 85 kWh, 300 kW, 10 minute charge
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Higher capacity electrodes will lower cost, improve specific energy, energy density
20% improvement in electrode capacity– Lowers cost by 1-3%– Lowers cell mass by 3-5%– Lowers cell volume by 5%
NMC622-Graphite85 kWh, 300 kW
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PROGRESS
Participate in meeting with collaborators and stakeholders– Status: Complete, September 2016
Report on fast-charging capabilities and path forward– Status: Report has been compiled
Milestones / Status
www.anl.gov
COLLABORATION
COLLABORATION
ANL, INL and NREL worked to assess state of technology
– Battery, infrastructure, vehicle, and market analysis teams
Participated in information exchange with stakeholders
– Automotive OEMs, utility, government agencies, battery developers,
EVSE manufacturers & network operators
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SUMMARY
Fast charging battery packs have been modeled to show
– Lithium plating limits the anode thickness and increases the pack cost
– Cell cost increases nonlinearly with decreasing charging times
– Cooling may be needed during charging, especially if the constraint
on lithium plating can be relaxed with improved electrodes
– Improved electrodes will lower the cost of battery packs
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PROPOSED FUTURE WORK
PROPOSED FUTURE WORK
Adapt BatPaC to incorporate design constraints for fast charge
Analyze case scenarios to identify opportunities that facilitate fast charge
Incorporate new experimental data from battery tests
Support R&D teams with projections using new data
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ACKNOWLEDGMENTS
DOE/VTO: David Howell, Steven Boyd, Brian Cunningham, Jack Deppe, SammGillard, Bob Graham, Lee Slezak
ANL Team: Ira Bloom, Andrew Burnham, Andy Jansen, Tom Stephens, Keith Hardy, David Robertson, Ram Vijaygopal
INL Team: Eric Dufek, Barney Carlson, Fernando Dias, Manish Mohanpurkar, Don Scofield, Matthew Shirk, Tanvir Tanim
NREL Team: Matthew Keyser, Cory Kreuzer, Anthony Markel, Andrew Meintz, Ahmad Pesaran, Jiucai Zhang
The authors are grateful for the sponsorship, guidance and technical support
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PUBLICATIONS
Enabling Fast Charging – A Battery Technology Gas Assessment, manuscript to be submitted to J of Power Sources